From the Guidelines
For a patient with hyponatremia and a sodium level of 123 mEq/L, the initial approach should be to restrict fluid intake to 1,000 mL/day and consider cessation of diuretics, as this is a case of moderate hyponatremia. The management strategy should prioritize the severity of symptoms and the underlying cause of hyponatremia. According to the guidelines by the American Association for the Study of Liver Diseases 1, water restriction to 1,000 mL/day and cessation of diuretics is recommended for moderate hyponatremia (120-125 mEq/L).
Key Considerations
- The use of hypertonic saline is generally reserved for short-term treatment of patients with symptomatic or severe hyponatremia, or those with imminent liver transplant 1.
- The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome 1.
- For patients with severe symptoms, such as confusion, seizures, or coma, more aggressive correction with hypertonic saline may be necessary, with careful monitoring to avoid overly rapid correction 1.
- Frequent monitoring of serum sodium levels is essential to adjust the treatment approach as needed.
Treatment Approach
- For asymptomatic or mildly symptomatic patients, fluid restriction is often the first step, particularly if the patient is euvolemic or hypervolemic.
- For hypovolemic hyponatremia, isotonic saline can be used until euvolemia is achieved.
- Addressing the underlying cause of hyponatremia is crucial, which may include discontinuing offending medications, treating SIADH with fluid restriction or medications, or managing heart failure or cirrhosis appropriately.
From the FDA Drug Label
Patients were randomized to receive either placebo (N = 220) or tolvaptan (N = 223) at an initial oral dose of 15 mg once daily. The dose of tolvaptan could be increased at 24-hour intervals to 30 mg once daily, then to 60 mg once daily, until either the maximum dose of 60 mg or normonatremia (serum sodium >135 mEq/L) was reached
To start hyponatremia fluids for a sodium level of 123 mEq/L, the initial dose of tolvaptan is 15 mg once daily. The dose can be increased at 24-hour intervals to 30 mg once daily, then to 60 mg once daily, until either the maximum dose of 60 mg or normonatremia (serum sodium >135 mEq/L) is reached 2.
From the Research
Treatment of Hyponatremia
To start hyponatremia fluids for a sodium level of 123, the following options can be considered:
- Isotonic saline for hypovolemic patients 3, 4
- Fluid restriction for euvolemic patients 3, 4
- Diuresis for hypervolemic patients 3
- Hypertonic saline for severe symptomatic hyponatremia 3, 5, 4, 6
- Vasopressin receptor antagonists (vaptans) for euvolemic and hypervolemic hyponatremia 5, 7
Classification of Hyponatremia
Hyponatremia can be classified based on volume status:
- Hypovolemic: treated with isotonic saline 4
- Euvolemic: treated with fluid restriction and/or vasopressin receptor antagonists 3, 4, 7
- Hypervolemic: treated with diuresis and addressing the underlying cause 3, 4
Severe Hyponatremia
For severe hyponatremia (sodium ≤ 120 mmol/L), a bolus of 250 mL NaCl 3% may be more effective than 100 mL in rapidly increasing serum sodium levels 6